Mechanical Circulatory Devices (MCDs) such as artificial hearts, Ventricular Assist Devices (VADs) and other blood circulating systems have become increasingly recognized as life saving devices for patients whose heart is diseased or has been injured by trauma or heart attack or other causes. VADs in particular, are recognized as a major life saving modality for assisting patients who suffer from congestive heart failure.
MCDs must be cormected to the natural blood circulation system of the body such as the heart and aorta. When designing an artificial heart or VAD, the inflow and outflow conduits are one of the most critical components. The conduits generally need to deal with a pulsatile or with a non-pulsatile flow, as well as with the flow negative pressures created by the MCD. The artificial conduit must finction within or outside the host patient's body. It must not introduce or allow the entry of bacterial or other contamination into the host's body or circulatory system. If the conduit does not fulfil these requirements, it may cause thrombosis pannus formation, blockage, twisting, knocking, and pulling or compressing the heart and adjacent organs.
Almost all blood conducting devices exhibit some degree of thrombus (blood clot formation). Thrombosis is a multifactorial phenomenon. Two major factors are the blood flow pattern and the properties of the material in contact with the blood. Research shows that the major causes of clotting in the current blood flow conduits are the use of thrombogenic materials and of designs which create undesired flow patterns such as turbulence, separation, recirculation, stasis (pooling), and high and very low shear stresses. Among specific factors related to the above, undesired flow patterns are often generated by the existence of crevices or the lack of smoothness on interior surfaces or at joints in the conduits. The risk of twisting and folding of the conduits can be extremely dangerous.
Another persistent problem with current conduits relates to their durability. Compression, tensile and torque forces act on the conduits, and current conduits have an insufficient fatigue resistance to these forces and are prone, to varying degrees, to be distorted. Moreover, suction generated by the MCD exposes the conduit to a negative pressure, which causes it to collapse.
Accordingly, there is a need of use of a conduit which provides sufficient strength and durability to prevent crevices or deformation where stress is exerted. In order to use such a strong conduit, there is a need to provide a suitable coupling to connect such a conduit to the MCD or a natural blood circulatory system. Flexibility, angulation, size and orientation of a conduit are all important factors that have to be considered in designing a conduit that is optimal in terms of performance, compression exerted on adjacent organs such as the lungs, heart, great vessels and displacement of the heart. The human chest anatomy, with various sizes and types for different bodies, is also one of the factors, dictating how these factors have to be considered in achieving anatomical fitness. The coupling needs to provide smooth internal transition between coupled components to reduce turbulence in the blood flow.
Therefore, there is a need of a conduit assembly which allows use of a conduit which provides sufficient strength and durability, and also provides flexibility in positioning such a conduit and smooth internal transition between coupled components.